The present invention relates to a process for manipulating components, in particular for the precise positioning of microcomponents, a microtool having an integrated release mechanism for carrying out the process, and a process for manufacturing the microtool or at least parts of the microtool, particularly a microgripper or gripper arm.
For the assembly of miniaturized systems or microcomponents, such as in microoptics, special demands are placed on the grippers used to manipulate the components that are to be assembled. Unlike grippers used for components having large surfaces, which are known from microelectronics, microoptical grippers, for example, must be able to grasp three-dimensional components by surfaces of varying geometry and place them with precision. However, these extremely small components exhibit some unusual behavior that is characterized by a decrease in volumetric effects and an increase in surface effects.
Conventional microgrippers are fabricated using the methods of precision mechanics. The microcomponent that is to be manipulated is normally picked up by suction in an integrated channel (vacuum gripper), by adhesion on a liquid film or drop (e.g., droplet), or by piezoelectrically activated actuators.
Common to all these methods or tools is that, due to the extremely low mass of the component to be manipulated, releasing the component once it has been held is very problematic. Even after the vacuum is turned off, the suction on the liquid film is removed, or the piezoelectric actuator is turned off, the adhesive forces produced in the gripper may be greater than the force of gravity on the component, so that release of the component is greatly hindered. In particular, it is frequently impossible to position the component precisely for accurate fitting on the target system if the component must be wiped off or blown off.
Precision manufacturing techniques such as drilling or milling are used in the conventional production of grippers made in the form of microtools. In the case of microtools having a typical size less than 2 mm, however, such precision methods of producing individual components are quite expensive.
The process for manipulating components according to the present invention, the microtool made according to the present invention for implementing the process, and the process for manufacturing the microtool or at least parts of the microtool have the advantage over the prior art that they make possible the simple, precise, and cost-effective micromechanical manufacture of a tool for precise manipulation, positioning, and particularly microassembly of components having typical dimensions in the micrometer range and lower millimeter range.
The microtool or individual microtool parts, particularly the gripper arm or microgripper, can be produced on a conventional silicon production line while, at the same time, the concrete design of the gripper arm or the gripping surface of the microtool can be given any desired two-dimensional form, so that in this way the geometry of the microtool can be quite easily adapted to the component that is to be manipulated. Moreover, the microtool manufacturing process in accordance with the present invention is suitable for batch production or series production, which makes it quite cost-effective.
Moreover, it is particularly advantageous if the process in accordance with the present invention for producing the microtool or microtool parts is based on the micropatterning of a layered structure having a base layer, an intermediate layer, and a structuring (patterning) layer, as previously known, for example, in the form of an SOI wafer (xe2x80x9csilicon on insulatorxe2x80x9d). Thus, the microtool can be easily patterned in a conventional manner out of the structuring layer by applying an additional masking layer suitable to the desired geometry of the microtool or microtool part being manufactured and then using a likewise conventional etching process.
Thus, the component held by the microtool is released in an advantageous manner using a plate structure arranged in the vicinity of a gripper arm, an actuator layer that is at least in part connected to the gripper arm, in particular a piezoelectric or piezoresistive layer, an ultrasound transmitter located in the vicinity of the gripper arm, or an actuator that is connected to and/or interacts with the gripper arm.
Moreover, it is advantageous if the microtool has at least two opposing, especially symmetrically arranged, gripper arms for holding a component. It is further advantageous if the gripper arms are connected to an anchor by a movable crosspiece or a soft spring. This anchor serves as a fixed point for the otherwise largely freely movable gripper arms.
In addition, it is advantageous if the designated actuator structure that is connected to the gripper arms is made in the form of an anchored comb structure and an associated comb structure on the leg of the gripper arms, thereby forming a conventional interdigital capacitor which can be used to cause the gripper arms to move and produce controlled attachment and release of the component.